Abstract
The North Celestial Pole Loop (NCPL) provides a unique laboratory for studying the early-stage precursors of star formation. Uncovering its origin is key to understanding the dynamical ...mechanisms that control the evolution of its contents. In this study, we explore the 3D geometry and the dynamics of the NCPL using high-resolution dust extinction data and H
i
data, respectively. We find that material toward Polaris and Ursa Major is distributed along a plane similarly oriented to the
Radcliffe
wave. The Spider projected in between appears disconnected in 3D, a discontinuity in the loop shape. We find that the elongated cavity that forms the inner part of the NCPL is a protrusion of the Local Bubble (LB) likely filled with warm (possibly hot) gas that passes through and goes beyond the location of the dense clouds. An idealized model of the cavity as a prolate spheroid oriented toward the observer, reminiscent of the cylindrical model proposed by Meyerdierks et al., encompasses the protrusion and fits into arcs of warm H
i
gas expanding laterally to it. As first argued by Meyerdierks et al., the nonspherical geometry of the cavity and the lack of OB stars interior to it disfavor an origin caused by a single point-like source of energy or multiple supernovae. Rather, the formation of the protrusion could be related to the propagation of warm gas from the LB into a pre-existing nonuniform medium in the lower halo, the topology of which was likely shaped by past star formation activity along the Local Arm.
Drawing on recent literatures that explore the complicated role of ‘Indigenous intermediaries’ within histories of geographical exploration, and bringing these into dialogue with research exposing ...the colonial nature of geographical knowledge, this article studies the ways in which information extracted from an Indigenous Arctic informant named Nocum was crucial in the formation of troubling geographical understandings regarding Inuit ‘origins’ and migration. The article analyses the extractive nature of the intellectual contributions offered by the American traveller and scholar William Healey Dall, and situates them amidst their troubling imperial and racialised context. The article concludes by arguing that geographers must continue to identify and reflect critically on the role of indigenous peoples within the historical (co)production of geographical knowledge, but that they must be equally attentive to the ways this knowledge was regularly used to inform and justify various forms of imperial intervention and colonial violence.
Short
The article analyses the extractive nature of the intellectual contributions offered by the American traveller and scholar William Healey Dall, and situates them amidst their troubling imperial and racialised context. The article argues that geographers must identify and reflect critically on the role of indigenous peoples within the historical (co)production of geographical knowledge but that they must be equally attentive to the ways this knowledge was regularly used to inform and justify various forms of imperial intervention and colonial violence.
The usefulness of the implantable loop recorder (ILR) with improved atrial fibrillation (AF) detection capability (Reveal XT) and the factors associated with AF in the setting of unexplained stroke ...were investigated.
A cohort study is reported of 51 patients in whom ILRs were implanted for the investigation of ischemic stroke for which no cause had been found (cryptogenic) following appropriate vascular and cardiac imaging and at least 24 hours of cardiac rhythm monitoring.
The patients were aged from 17 to 73 (median 52) years. Of the 30 patients with a shunt investigation, 22 had a patent foramen ovale (73.3%; 95% confidence interval CI 56.5%-90.1%). AF was identified in 13 (25.5%; 95% CI 13.1%-37.9%) cases. AF was associated with increasing age (p = 0.018), interatrial conduction block (p = 0.02), left atrial volume (p = 0.025), and the occurrence of atrial premature contractions on preceding external monitoring (p = 0.004). The median (range) of monitoring prior to AF detection was 48 (0-154) days.
In patients with unexplained stroke, AF was detected by ILR in 25.5%. Predictors of AF were identified, which may help to target investigations. ILRs may have a central role in the future in the investigation of patients with unexplained stroke.
Abstract
We introduce the HOTT dust optical depth and temperature maps parameterizing thermal dust emission. Such maps have revolutionized studies of the distribution of matter in molecular clouds ...and processes relevant to star formation, including virial stability. HOTT maps for a suite of fields, including the Herschel Gould Belt Survey, are available online. The standardization of our robust pipeline for modified blackbody fitting of the spectral energy distribution (SED) of high-quality archival submillimeter data from the Herschel Space Observatory is based on a thorough analysis and quantification of the uncertainties of the data. This enables proper weighting in the SED fits. The uncertainties assessed fall into four main categories: instrument noise; the cosmic infrared background anisotropy, a contaminating sky signal; gradient-related noise arising because of dust signal morphology; and calibration uncertainty, scaling with the signal strength. Zero-level adjustments are important too. An analysis of residuals from the SED fits across many fields supports the overall appropriateness of the assumed modified blackbody model and points to where it breaks down. Finding
χ
2
distributions close to the theoretical expectation boosts confidence in the pipeline and the optimized quality of the parameter maps and their estimated uncertainties. We compared our HOTT parameter maps to those from earlier studies to understand and quantify the potential for systematic differences.
The Notch receptor is an evolutionarily highly conserved transmembrane protein essential to a wide spectrum of cellular systems, and its deregulation has been linked to a vast number of developmental ...disorders and malignancies. Regulated Notch function is critical for the generation of T-cells, in which abnormal Notch signaling results in leukemia. Notch activation through
-activation of the receptor by one of its ligands expressed on adjacent cells has been well defined. In this canonical ligand-dependent pathway, Notch receptor undergoes conformational changes upon ligand engagement, stimulated by a pulling-force on the extracellular fragment of Notch that results from endocytosis of the receptor-bound ligand into the ligand-expressing cell. These conformational changes in the receptor allow for two consecutive proteolytic cleavage events to occur, which release the intracellular region of the receptor into the cytoplasm. It can then travel to the nucleus, where it induces gene transcription. However, there is accumulating evidence that other pathways may induce Notch signaling. A ligand-independent mechanism of Notch activation has been described in which receptor processing is initiated
cell-internal signals. These signals result in the internalization of Notch into endosomal compartments, where chemical changes existing in this microenvironment result in the conformational modifications required for receptor processing. This review will present mechanisms underlying both canonical ligand-dependent and non-canonical ligand-independent Notch activation pathways and discuss the latter in the context of Notch signaling in T-cells.
Background
It remains unknown whether laparoscopic compared to open surgery translates into fewer incisional hernia repairs (IHR). The objectives of the current study were to compare the long-term ...incidence of IHR and the size of repaired hernias between patients subjected to laparoscopic or open resection of colonic cancer.
Methods
This was a nationwide cohort study comprised of patients undergoing resection for colonic cancer between January 2007 and March 2016 according to the Danish Colorectal Cancer Group database. Patients who subsequently underwent IHR were identified in the Danish Ventral Hernia Database, from which information about the priority of the hernia repair and the size of the fascial defect was retrieved.
Results
The study included 17,717 patients, of whom 482 (2.7%) underwent subsequent IHR during a median follow-up of 4.7 (interquartile range 2.8–6.9) years. There was no significant difference in the 5-year cumulative incidence of hernia repair after laparoscopic compared to open colonic resection (3.9%, CI 3.3–4.4% vs 4.1%, CI 3.5–4.6%). After adjustment for confounders, laparoscopic approach was associated with an increased rate of emergency IHR (HR 2.37, 95% CI 1.03–5.46,
P
= 0.042) as opposed to elective IHR (HR 0.91, 95% CI 0.73–1.14,
P
= 0.442). Laparoscopic surgery was significantly associated with a decreased fascial defect area compared to open surgery (mean difference −16.0 cm
2
, 95% CI −29.4 to −2.5,
P
= 0.020).
Conclusions
There was no difference in the incidence of IHR after open compared to laparoscopic resection. Compared to the open approach, laparoscopic resection increased the rate of subsequent emergency IHR, suggesting that a more aggressive therapeutic approach may be warranted in this patient group upon diagnosis of an incisional hernia.
Abstract
We propose polarization of scattered optical light from intermediate Galactic latitude infrared cirrus as a new diagnostic to constrain models of interstellar dust and the anisotropic ...interstellar radiation field (aISRF). For single scattering by a sphere, with Mie scattering phase functions for intensity and polarized intensity for a dust model at a given wavelength (Sloan
r
and
g
bands), and with models of anisotropic illumination from the entire sky (represented in HEALPix), we develop the formalism for calculating useful summary parameters for an integrated flux nebula (IFN): the average of the phase function weighted by the illumination, polarization angle (
ψ
), and polarization fraction (
p
). To demonstrate the diagnostic discrimination of polarization from scattered light, we report on the effects of different anisotropic illumination models and different dust models on the summary parameters for the Spider IFN. The summary parameters are also sensitive to the IFN location, as we illustrate using FRaNKIE illumination models. For assessing the viability of dust and aISRF models, we find that observations of
ψ
and
p
of scattered light are indeed powerful new diagnostics to complement joint modeling of the intensity of scattered light (related to the average phase function) and the intensity of thermal dust emission. However, optically thin IFNs that can be modeled using single scattering are faint and
p
is not large, as it could be with Rayleigh scattering, and so these observations need to be carried out with care and precision. Results for the Draco nebula compared to the Spider illustrate the challenge.
Abstract
The physical properties of galactic halo gas have a profound impact on the life cycle of galaxies. As gas travels through a galactic halo, it undergoes dynamical interactions, influencing ...its impact on star formation and the chemical evolution of the galactic disk. In the Milky Way halo, considerable effort has been made to understand the spatial distribution of neutral gas, which is mostly in the form of large complexes. However, the internal variations of their physical properties remain unclear. In this study, we investigate the thermal and dynamical state of the neutral gas in high-velocity clouds. High-resolution observations (1.′1) of the 21 cm line emission in the EN field of the DHIGLS H
i
survey are used to analyze the physical properties of the bright concentration CIB located at an edge of a large HVC complex, complex C. We use the Gaussian decomposition code
ROHSA
to model the multiphase content of CIB and perform a power spectrum analysis to analyze its multiscale structure. The physical properties of some 200 structures extracted using dendrograms are examined. Each phase exhibits different thermal and turbulent properties. We identify two distinct regions, one of which has a prominent protrusion extending from the edge of complex C that exhibits an ongoing phase transition from warm diffuse gas to cold dense gas and filaments. The scale at which the warm gas becomes unstable and undergoes thermal condensation is about 15 pc, corresponding to a cooling time of about 1.5 Myr. Our study characterizes the statistical properties of turbulence in the fluid of an HVC for the first time. We find that a transition from subsonic to transonic turbulence is associated with the thermal condensation, going from large to small scales. A large-scale perspective of complex C suggests that hydrodynamic instabilities are involved in creating the structured concentration CIB and the phase transition therein. However, the details of the dynamical and thermal processes remain unclear and will require further investigation through both observations and numerical simulations.
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